It is well known that thermoplastic injection molding requires a part design limited to relatively thin walls (for rapid cooling in the mold) and having an overall geometry which permits release from the mold when the mold is opened. These requirements are inconsistent with the geometry of balls.
Currently balls are made by other manufacturing processes such as, rotational molding, blow molding or thermoset molding.
The present invention is a ball suited to injection molding from soft thermoplastic elastomer. In addition, the ball of the present invention can be made very soft and compressible.